Stock consistency regulator



Dec. 3, 1935. 5, STAEGE 2,023,106

STOCK CONSISTENCY REGULATOR Filed May 11, 1934 2 Sheets-Sheet 1 WTNESSES: I |NVENTOR v Slap/75v? A. Szaege.

W Y m y A'TToRNEY WWW-W Gil Patented Dec. 3, 1935 2,023,106

UNITED STATES PATENT OFFICE 2,023,106 STOCK CONSISTENCY REGULATOR Stephen A. Staege, Pittsburgh, Pa., asslgnor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a. corporation of Pennsylvania Application May 11, 1934, Serial No; 725,093

I 12 Claims. (Cl. 9H6) My invention relates to control systems for Referring morev particularly to Fig. 1, a vertimotors and more particularly to systems for concal pipe or tube l is provided along which the may be unsatisfactory, namely, the weight of the more fully explained hereinafter. 15

in certain process. controlled by grids I5 and 56, respectively.

of making paper is not, however, the To properly measure and control the con- The ar only field of application of my invention, since sistency of the stock 2 in the tube l, a pair of factunng processes, the amount of liquid or solul. The pipe 33 is an intake pipe and pipe 35 tion of a liquid with reference to the solid mateis a discharge pipe discharging the material or rial is very important. stock 2 at substantially the same point in the pipe One object of my invention is to control the i, so that any pressure in the stock 2 will not amount of liquid that is supplied to a material affect the operation of the propeller vanes 32 that the consistency of the material maybe mainouter ends of the pipes 33 and 35.

tained substantially constant. A synchronous motor 28, whose field winding A more specific object of my invention is to 30 is suitably excited from a suitable source 29 control the consistency of paper stock by apthrough shaft 3i, and drives the suitable reducof manufacturing. these vanes are driven at a speed sufficiently slow 35 Other'objects and advantages will become more to prevent the material from being thrown away cation when considered in conjunction with the is thus a true indication of the consistency of accompanying drawings, in which: the material in the pipe 6. The torque of the Figure 1 is a diagrammatic view of a system motor 28 also determines the angular displace- 40 of control for supplying water to paper stock by ment of the rotor of motor 28 with reference to the use of a pair of hot cathode electric disthe rotating field of this motor.

charge devices and a magneto alternator; A small alternator 24 having its field winding Fig. 2 is a diagrammatic view of a modification 22 suitably excited from a suitable source 2! of my invention utilizing an impulse generator mounted on the shaft 3! and when motor 28 and a pair of Ignitron tubes; is in synchronism with the frequency of the en- Fig. 3 is a diagrammatic view of a further ergy supplied to the generator 24 generates an Fig. 4 is a view, partly in elevation and partly thus supplied with a cycle current from the in section, of a modified stock-sampling device, rotating member or armature windings 23 of the stead of using hot cathode 2 nator 24 is such that the bias of the grids l5 and I9 through the secondary winding 25 and the resistors 26 and 21 causes the field winding 5 to be properly excited. That is, the bias of the grids with reference to the anode is such that the discharge devices 6 and 1 break down at such portion of each cycle of the alternating current supplied by the secondary of the transformer 9 that the field winding 5 is properly energized and.

the motor 4 rotates at just such speed that the pump-3 supplies of water to the stock 2.

If for any reason the consistency is not correct or, let us assume, the amount of water being added to the stock 2 is not sufficient, the relation of the amount of water to the solid material decreases and as a consequence, the viscosity and the load increases and the rotor 28 of the synchronous motor is caused to lag with reference to the rotating field flux by a somewhat greater angle than for normal operation. When this takes place, the alternating current supplied to the grids by the alternator 24 shifts its phase with reference to the alternating current supplied to the anodes of the respective tubes and the bias is shifted in such a direction that a smaller amount of current per cycle is rectified by the discharge devices 6 and 1. In consequence, the excitation of field winding 5 is decreased with the result that the speed of the motor 4 increases to increase the speed of the pump 3, thereby adding more water.

The regulation is very sensitive, since the pump may be a centrifugal pump and for the particular' application illustrated operates against a constant head so that any slight variation in the speed of the motor 4 will cause an immediate change in the amount of moisture supplied to the stock 2.

The circuit for the field winding 5 may be traced from the midpoint of the secondary ID of the transformer 9 through conductor 11, field winding 5, conductor 19, the secondary winding 1 l, cathode l3 and anode l9 to the left-hand terminal of the secondary l9 and, for the second half of the cycle, the circuit is established from the midpoint of the transformer secondary 19 through conductor 11, field winding 5, conductor l8, secondary I2, cathode l4 and anode 2D to the right-hand terminal of the secondary 19 of the transformer 9.

When too much water is added to the stock 2, the viscosity is lowered and the torque on motor 28 will naturally decrease and as a result the current generated by the alternator 24 will shift its phase position with reference to the principal electrodes of the electric discharge devices 6 and 1 in such a direction as to increase the correct amount the amount of current rectified by these tubes,

thereby increasing the excitation of the field winding 5 to decrease the speed of motor 4 and thus of pump 3, thereby adding less water to the stock 2.

In the modification shown in Fig. 2, elements corresponding in every respect to the elements shown in Fig. 1 have corresponding reference characters. However, in this modification, in-

tubes, which have a comparatively limited current capacity, a pair of Ignitron tubes 31 and 38 are utilized, which Ignitron tubes have their respective anodes 4| and 42 connected to the secondary of the transformer 99 and the cathodes 39 and 40 connected to one terminal of the armature winding of motor 4 through conductor 19. The other terminal of that the amount of current passing through an in Ignitron tube can be very effectively controlled. To control the ignition of the Ignitron tubes 31 and 38, an impulse generator 43 is mounted on the shaft of the synchronous motor 28. This impulse generator has a pair of rotating windings or poles 48 and 49 suitably energized from a source of supply 41. The stationary part 44 of the impulse generator 43 is provided with suitable gearing so that the position of the stator with reference to the shaft of the synchronous 20 motor 28, when in a given position, may be properly selected.

The stationary part 44 is provided with a pair of stationary pole windings 59 and 54 which can obviously be shifted about the shaft of the synchronous motor 28, so that ignition of the Ignitron tubes 31 and 38 may be affected at any selected point on the alternating current wave. The winding 59, by a circuit through conductor 5|, ignition contact member 52, cathode 39 and conductor 53, .is connected to ignite the Ignitron tube 31, whereas winding 54, by a circuit through conductor 55, ignition terminal or contact member 56, cathode 40 and conductor 51 is adapted to ignite Ignitron tube 38. By properly operating the handwheel 46, the stator 44 may be so positioned that just the right amount of speed is secured for motor 4 for a given operation.

Since the moisture supplied to the material 40 and also the operating conditions vary, it is clear that some sort of control or regulation is needed to vary the speed of motor 4 proportional to the actual consistency of the stock 2. This is accomplished by the coaction of the synchronous motor 28 and the impulse generator 43. If the amount of water added is not sufficient, the torque on motor 28 increases and in consequence, the rotating poles 48 and 49 pass the stationary poles 50 and 54 later with reference to the alternating current waves on the tubes, with the result that the ignition of the respective tubes 31 and 38 the cycle of alternating current supplied to these tubes that the excitation ing is increased. Motor 4 thus increases in speed, thereby supplying a greater amount of moisture, or water, to the stock 2 by the pump3.

When too much moisture is added to the stock 2, the motor 29 operates below normal torque and pole pieces 49 and 49 pass the pole pieces 59 and 54 earlier with reference to the alternating current means impressed on the tubes, and the result is that the excitation of the armature winding is decreased, thereby decreasing the speed of the motor 4 and thus decreasing the amount of water added to the stock.

In the modification shown in Fig. 3, Ignitron tubes are again utilized but these Ignitron tubes 70 of the armature wind- 55 This direct current motor has its 75 I 2,023,106 r 3 field winding 15 energized from a constant voltapparatus and method of sampling the stock. By age exciter 12 driven by amotor 1|. taking the stock sample from a given point in the Since exciter 12 is of the constant ,voltage main pipe line I carrying the stock and returning type, a constant potential will be impressed across the sample to the same pressure point in the line I, terminals or buses 13 and 14 and, in consequence, any variations in pressure in the stock pipe line the field winding 62 of the motor 60 driving the will have substantially no effect upon the rotating fected by varying the voltage supplied to the the stock is taken out and the point where the armature 6! of the motor 60. stock is returned, such pressure difierence would To appropriately control the grid bias of the have a decided effect upon the power required to grids 95 and 94 of the respective Ignitron tubes, rotate the vanes or conveyor auger. It will be a three-core reactor 80 is utilized which has a noted that the tubes 33 and enter the main pipe pair of windings 81 and 88 connected across a at right angles thereto and project a distance of the three-core reactor. The secondary windvice an intake sampling tube I33 extends to the ing of this transformer 92 has its outer termicentral or axial region of the pipe I01. Tube 33 nals connected to the grids 94 and 95, respecis connected to the propeller or conveyor housing tively, through the resistors 96' and 91, respec- I34 at the middle thereof. A conveyor consists 35 98 and i i i terminal I am aware that the three modifications herein- As the saturation of the three-core reactor vabefore i l d and sho n in the accompanying s, t am u t f current e tifi d y the I nidrawings are merely illustrative of my invention in an oppo te sense, namely, when the o que to the specific circuit arrangements shown but is 011 armature 77 decreases the amount 6111" only to be limited by the pertinent prior art and rent rectified by Ignitron tubes 520 and 1128 det claims appended t t specificatjon creases and the amount of current supplied to the I dafim as my invention;

armature decreases to decrease the Speed 1. In a system for controlling the consistency of h p p The circuit for the armature material by controlling the amount of liquid added may be traced from the m dpo nt of t secondto the material, .in combination, a conveyor for e y oi t s m 99 t u h conductor $3, the material ineans for adding liquid to the maarmature 6i, conductor 64, cathode G5, anode t 1, t having field winding for op- 69 and anode 10 t0 the left-hand terminal of the thereof, and means controlled by the means r econd y W n n t0 the mer sponsive to the consistency of the material to con- An impo tant eat o y i nt is he trol the operating characteristics of the electric discharge devices to thus control the speed of the motor operating said liquid-adding means, whereby the consistency of the material is maintained substantially constant.

2. In a system for controlling the consistency of material, in combination, material, means for diverting a portion of the material from the conveyor through a conduit, means associated with said conduit to be responsive to the consistency of the material, an electric discharge device controlled in its operating characteristics by the means responsive to the consistency of the material, a pump adapted to supply liquid to the material, a motor for driving the pump, and means controlled by said electric discharge devices to control the speed of the motor operating the pump in a manner to maintain the consistency of the material substantially constant.

3. In a device for controlling the consistency of paper stock by adding liquid to the stock, in combination, a tube for conveying the stock, a sampling device disposed at a given point along the tube for conveying the stock, operating means for the sampler, means responsive to variations of the liquid content in the paper stock, means for adding liquid to the paper stock, and an electric discharge device controlled by the means responsive to the consistency of the stock for controlling the means for adding liquid to the stock.

4. In a system of control for controlling the consistency of paper stock, a sample tube, a propeller in the tube for moving the paper stock, a synchronous motor for driving the propeller, a pump for adding liquid to the stock, a motor, having a field winding, for driving the pump, an electric discharge device for energizing the field winding of the motor operating the pump to control the speed thereof, and means responsive to the mechanical displacement of the rotor of the synchronous motor operating the propellers with reference to its rotating field to control the operation of the electric discharge device to thus control the speed of the motor operating the pump.

5. In a system of control, an electric discharge device having a pair of principal electrodes, and a control electrode, means for supplying alternating current to the principal electrodes, an alternator normally supplying an alte nating current potential to the control electrode having a certain phase relation with reference to the alternating current supplied to the principal electrodes, means for shifting the phase position of the alternating current generated by the alternator with reference to the alternating current supplied to the principal electrodes to thus control the operating characteristics of the electric discharge device, a conveyor for material, means responsive to the consistency of the material to control the operation of the alternator, means for adding liquid to the material, a motor for driving the means for adding the liquid to the material, said motor having a field winding, and circuit connections for interconnecting the field winding of the motor with the electric discharge device whereby the speed of the motor is controlled in response to the variations in operating characteristics of said electric discharge device.

6. In a device for controlling the consistency of material, in combination, a conveyor for the material, a pump for adding liquid to the material, a motor for operating the pump, and means responsive to the liquid content in the material adapted to control the speed of the motor operating the a conveyor for the pump to thus control the liquid content in the material.

'1. In a system of control for controlling the consistency of material by the addition of an ap-, propriate amount of liquid thereto, in combination, a sampling conveyor, a propeller in said conveyor, means for driving the propeller, means associated with said driving means to be responsive to the variations in the consistency of the material acted upon by said propeller, an electric discharge device whose operating characteristics are a controlled by the means responsive to the consistency of the material, and means controlled by said electric discharge device to control the amount of liquid being added to the material to maintain the consistency substantially constant.

8. In a system of control for controlling the consistency of material, in combination, a conveyor for the material, a propeller for moving the material in said conveyor, a motor for driving the propeller, electric discharge devices controlled by the torque of said motor, and means controlled by the variation and operating characteristics of said electric discharge device for liquid to the material.

9. In a system of control for controlling the consistency of material, a conveyor for the material, a closed-circuit sampling conduit for taking a sample from said conveyor, a motor for moving the material through said sampling tube, an impulse generator mounted on the shaft of said motor and responsive in the generation of its impulses to the torque of said motor, an Ignitron tube adapted to be ignited by said impulse generator as a function of the torque on said motor, a pump for adding liquid to the material in the conveyor, a motor for driving the pump, and circuit connections interconnected with said Ignitron tube for controlling the speed of the motor operating the pump to thus maintain the consistency of the material substantially constant.

10. In a system for controlling the consistency of paper stock, in combination, a tube along which the stock is moved, a closed-circuit conduit for taking a sample at a given point along the tube, a propeller in the closed-circuit conduit for moving the sample of material through said conduit, a synchronous motor for driving the propeller, an impulse generator adapted to generate voltage impulses whose phase position with reference to the rotating field of the synchronous motor is determined by the torque on said motor, an Ignitron tube adapted to be ignited by said voltage impulses of said impulse generator, a motor having a field winding interconnected with the Ignitron tube whereby the speed of the motor is controlled by the Ignitron tube, and a pump driven by said last-named motor and adapted to add liquid to the stock.

11. In a system of control for controlling the amount of liquid to be added to a material to control its consistency, in combination, a conduit for the material, a pump for adding liquid thereto, a motor for driving the pump, a closed circuit sampling conduit adapted to take a sample at a given point along the conduit and return the sample to the conduit at substantially the same point, a propeller in the sampling conduit, a motor for driving the propeller, a three-core reactor, circuit connections for controlling the saturation of said three-core reactor as a function of the torque of the motor driving the propeller, electric discharge devices controlled by said three-core reactor, and circuit connections interconnecting the motor driving the pump and the electric disadding propeller in said sampling conduit, a motor for driving the propeller, a three-core reactor responsive to the torque of the motor driving the propeller, a grid-controlled Ignitron tube, circuit connections with the thr interconnecting the grid of the tube ee-core reactor whereby the ignition of the Ignitron tube is controlled as a function of the torque of the motor driving the propeller, a 5 pump for adding liquid to the tube, and circuit termined by Ignitron tub material.

the operating characteristics of the 10 e and thus by the consistency of the STEPHEN A. STAEGE. 

